title: Bostrycin and 4-deoxybostrycin: two nonspecific phytotoxins produced by Alternaria eichhorniae.
abstract: Two crystalline red pigments with phytotoxic activity were isolated from culture filtrates of Alternaria eichhorniae, a pathogen of the water hyacinth Eichhornia crassipes. The pigments were present in the ratio of 4:1 and were identified as bostrycin and 4-deoxybostrycin, respectively. This is the first isolation of 4-deoxybostrycin from a natural source. Bostrycin, 4-deoxybostrycin, and their isopropylidene derivatives induced necrosis on tested plant leaves comparable to the A. eichhorniae-induced necrosis on water hyacinth. The lowest phytotoxic concentrations of crystalline bostrycin and 4-deoxybostrycin on water hyacinth leaves were about 7 and 30 microgram/ml, respectively. Both substances were inhibitory to Bacillus subtilis but were inactive against the fungus Geotrichum candidum.
mesh_terms: D000528:Alternaria / Q000032:analysis*; D000880:Anthraquinones / Q000302:isolation & purification* / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D005848:Geotrichum / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D003904:Mitosporic Fungi / Q000032:analysis*; D010860:Pigments, Biological / Q000302:isolation & purification / Q000494:pharmacology; D010944:Plants / Q000187:drug effects; D013053:Spectrophotometry
chemical_list: D000880:Anthraquinones; D010860:Pigments, Biological; C034287:bostrycin; C034288:4-deoxybostrycin